Controlling microbial growth in beverage compositions is an ongoing concern among beverage manufacturers. Such beverage compositions, when exposed to food spoilage microorganisms, provide an excellent environment for rapid microbial growth, particularly wherein the beverage compositions contain fruit juice. Such exposure can result from accidental inoculation of the beverage compositions during manufacturing or packaging. Food spoilage microorganisms can then rapidly proliferate by feeding on nutrients provided by, for example, the fruit juice component of the beverage compositions.
Microbial proliferation is not likely to occur without the requisite exposure to yeast or bacteria. Manufacturing and packaging operations directed to the prevention of such exposure is preferred, but provisions are often made for any infrequent accidental exposure to the isolated beverage composition. Such provisions are directed to limiting or preventing subsequent microbial proliferation to thus limit or prevent food spoilage.
Microbial stability of beverage compositions can be provided to some extent by heat pasteurizing during packaging (hot packing) or by packaging under completely aseptic conditions (aseptic packaging). Hot packing involves pasteurization of the beverage and its container such that the resulting sealed beverage contains no food spoilage microorganism. Likewise, aseptic processing and packaging of a pasteurized beverage will produce a beverage product which is free of food spoilage microorganisms. Accordingly, these beverages are extremely shelf stable since there are no food spoilage microorganisms therein to feed on the beverage nutrients and rapidly proliferate.
Aseptic packaging methods, however, are often unsuitable for manufacturing beverages packaged in certain beverage containers, e.g., rigid containers such as glass, plastic and cans. Moreover, an aseptic or sterile environment is difficult to maintain during aseptic packaging operations. Frequent cleaning of the packaging line is necessary which is time consuming and expensive.
Hot packing methods are likewise unsuitable for manufacturing certain types of beverages. Hot packing involves heat pasteurization of the juice beverage during packaging at temperatures of from about 85° C. to about 105° C. This method is commonly utilized in the manufacture of canned or bottled (glass) beverages. However, not all beverage containers can withstand heat-pasteurization during packaging. For example, flexible containers made from high density polyethylene, which have become more popular with consumers, should not be subjected to the pasteurization temperatures utilized during hot packing operations.
In an effort to avoid such hot packing or aseptic processing, preservatives have been used in beverages to provide some degree of microbial inhibition. Preservatives commonly used in beverage products include, for example, sorbates, benzoates, organic acids, and combinations thereof. However, when utilized in the absence of other ingredients which can provide an anti-microbial effect, such preservatives often contribute an off-flavor to the beverages when used at the levels necessary to inhibit subsequent microbial proliferation during storage.
It has previously been discovered that certain noncarbonated dilute juice beverage products could be maintained at ambient temperatures for at least about 10 days without substantial microbial proliferation therein by incorporating a preservative with a linear polyphosphate. In such products, at least about 100 ppm of a preservative selected from sorbic acid, benzoic acid, alkali metal salts thereof and mixtures thereof is utilized in combination with various amounts of polyphosphate and prescribed water hardness levels. Such products are found to be microbially stable and quite effective for use in beverage products.
In working with such beverage products, however, the present inventors have quite surprisingly discovered that the level of preservative (i.e., the sorbic acid, benzoic acid, alkali metal salts thereof, and mixtures thereof) can be decreased when utilized in combination with polyphosphate, with an unexpected maintenance of anti-microbial efficacy. This result was unexpected in that it had been believed that about 100 ppm of preservative was the lowest threshold available to deliver such efficacy. Moreover, this result is quite advantageous, as it allows decreased levels of preservative which, in turn, results in a lower cost beverage composition which may be more appealing to the consumer from the aspect of flavor. These and other benefits are realized by the present invention as will be described in more detail below.